Increasingly, existing large datasets (such as the Geriatrics and Extended Care Data and Analysis Center [GEC-DAC] dataset) and prospective observational/quasi-experimental studies are being used to examine important research questions in seriously ill older adults and to explore new models of care delivery. Randomized controlled trials can be burdensome to seriously ill patients or infeasible to conduct, and they may not produce results generalizable to the population of interest. Observational data analyses in geriatric palliative care must account for severe treatment endogeneity, which occurs when factors are simultaneously associated with treatment likelihood and outcomes. Propensity scores are one way to address endogeneity. A propensity score is the estimated probability of treatment receipt, conditional on a set of observed covariates that are thought to be associated with both treatment likelihood and outcome. An unbiased treatment effect can be estimated by comparing treated and comparison individuals with similar propensity scores. Most guidance on propensity scores is restricted to methods for matching individuals with similar propensity scores across two groups (treatment, no treatment). Many treatments, however, have multiple levels, and restricting treatments to binary indicators obscures differences between groups. Weighting by propensity scores is a superior alternative to matching when there are multiple treatment groups. This study aims to develop best practices for using propensity scores for multimodal treatments and to strengthen researchers? abilities to use existing VHA data to improve health care value and efficiency for older veterans. Specifically, this study will 1) Use simulated data to determine which weighting/estimation combination (inverse probability weighting or kernel weighting by propensity scores estimated via regression with maximum likelihood estimation, covariate- balancing propensity score estimation, or generalized boosting methods) provides the most efficient estimates with the least bias in a variety of estimation scenarios, 2) Determine which weighting/estimation strategy provides the best observed covariate balance (a secondary measure of propensity score performance) across multiple treatment levels in a variety of simulated estimation scenarios, and 3) Determine which weighting/estimation strategy is the least susceptible to residual confounding. Traditional Monte Carlo and plasmode (empirically based) simulations will be used to achieve the aims. To facilitate translation of results, we will repeat Aims 2 and 3 in empirical datasets with different sample sizes and expected treatment effect heterogeneity. Results will be verified by estimating effects of sedative-hypnotics on risk of in-hospital death in previously collected data from a study of 100,000 hospitalized veterans with cancer, heart failure, chronic obstructive pulmonary disease, and/or HIV/AIDS and from a study of 300,000 veterans with an opioid prescription. We expect to identify patterns of superior performance for strategies in common estimation scenarios as well as scenarios in which inferences are most likely to diverge. We will develop training materials based on our results and work with an advisory committee of leaders in observational data analysis to disseminate these results widely and inform studies of non-randomized health care interventions (such as post-hospitalization referral to Geri-PACT) as well as studies using VHA ?big data? resources.

Public Health Relevance

The results of this study will be used to develop best practices for using propensity scores for multimodal treatments and to strengthen researchers? abilities to use existing Veterans Health Administration data to improve health care value and efficiency for older veterans. If selection bias is ignored, we run the risk of erroneously concluding a helpful treatment has no statistically or clinically significant benefit, or erroneously concluding a treatment is safe when in fact it leads to harm. Careful targeting of VHA resources to sustain pilot interventions most likely to reduce veteran wait and travel times, improve symptom control, and reduce unnecessary hospitalizations depends on accurate interpretation of observational data analyses. Improving methods for addressing observable selection bias is essential to sustaining a high-functioning learning health care system.

National Institute of Health (NIH)
Veterans Affairs (VA)
Non-HHS Research Projects (I01)
Project #
Application #
Study Section
Healthcare Informatics (HS3A)
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
James J Peters VA Medical Center
United States
Zip Code
Streja, Elani; Kovesdy, Csaba Pal; Soohoo, Melissa et al. (2018) Dialysis Provider and Outcomes among United States Veterans Who Transition to Dialysis. Clin J Am Soc Nephrol 13:1055-1062
Garrido, Melissa M (2018) Robust Evaluations of Intensive Care Unit Length of Stay Using Observational Data. J Palliat Med 21:280
Molnar, Miklos Z; Eason, James D; Gaipov, Abduzhappar et al. (2018) History of psychosis and mania, and outcomes after kidney transplantation - a retrospective study. Transpl Int 31:554-565
Gellad, Walid F; Thorpe, Joshua M; Zhao, Xinhua et al. (2018) Impact of Dual Use of Department of Veterans Affairs and Medicare Part D Drug Benefits on Potentially Unsafe Opioid Use. Am J Public Health 108:248-255
Sumida, Keiichi; Molnar, Miklos Z; Potukuchi, Praveen K et al. (2018) Treatment of rheumatoid arthritis with biologic agents lowers the risk of incident chronic kidney disease. Kidney Int 93:1207-1216
Lu, Jun Ling; Molnar, Miklos Z; Sumida, Keiichi et al. (2018) Association of the frequency of pre-end-stage renal disease medical care with post-end-stage renal disease mortality and hospitalization. Nephrol Dial Transplant 33:789-795
Ornstein, Katherine A; Garrido, Melissa M; Siu, Albert L et al. (2018) Impact of In-Hospital Death on Spending for Bereaved Spouses. Health Serv Res 53 Suppl 1:2696-2717
Kovesdy, Csaba P; Naseer, Adnan; Sumida, Keiichi et al. (2018) Abrupt Decline in Kidney Function Precipitating Initiation of Chronic Renal Replacement Therapy. Kidney Int Rep 3:602-609
Beckman, Joshua A; Duncan, Meredith S; Alcorn, Charles W et al. (2018) Association of Human Immunodeficiency Virus Infection and Risk of Peripheral Artery Disease. Circulation 138:255-265
Streja, Elani; Kalantar-Zadeh, Kamyar; Molnar, Miklos Z et al. (2018) Radical versus partial nephrectomy, chronic kidney disease progression and mortality in US veterans. Nephrol Dial Transplant 33:95-101

Showing the most recent 10 out of 27 publications